The company said Monday it expected most of the affected workers to leave by year-end.

The layoffs are part of a move announced in June to eliminate 1,500 jobs in the aeronautics business as Lockheed cut costs in response to pressure to limit U.S. defense spending.

Spokeswoman Laura Siebert said 370 of the layoffs will be salaried executive and administrative workers in Fort Worth, Texas, where the company has 15,000 employees and a mile-long assembly line. Another 115 jobs will be eliminated in Marietta, Ga., and 55 in Palmdale, Calif.

The layoffs came a month after 450 employees took buyouts and agreed to leave by the end of the year. The company also eliminated 300 unfilled spots and cut 300 jobs at an aircraft-maintenance plant in Greenville, S.C., earlier this year.

Lockheed, based in Bethesda, Md., makes military aircraft including the F-35, F-22 and F-16 fighter jets, C-130 and C-5 cargo and transport planes, and P-3 and U-2 surveillance aircraft.

Siebert said Monday’s layoffs were not related to any particular programs but rather to a need to reduce overall costs

The company has about 126,000 employees, including 28,000 in its aeronautics business. In June, it cut 1,200 jobs in its space-systems equipment division.

Last year, Lockheed earned $2.9 billion on $45.8 billion in revenue, with 84 percent of sales going to the U.S. government. But in this year’s second quarter, revenue growth slowed to 2 percent and profit fell 10 percent, partly on charges for severance pay and higher pension costs.

Lockheed Martin shares rose $1.69, or 2.3 percent, to close at $73.78. They have ranged between $66.36 and $82.43 in the past year, and dropped sharply in late July and early August, as investors grew more worried that Congress and the Obama administration will limit or cut defense spending.